In some network deployments, wireless client devices (e.g., Windows® client) fail to obtain a dynamic host configuration protocol (DHCP) address due to temporary issues. In such scenarios, a wireless client device may decide to self-assign an automatic Internet Protocol (IP) address (e.g., 169.254.X.X). As such, the wireless client devices with the automatic IP address can only communicate within Layer-2 domains, but cannot communicate in Layer-3 domains, because a router is typically programmed to drop a packet having a source IP address that is automatically generated with 169.254.X.X.
Wireless client devices often encounter the above-mentioned DHCP issues intermittently. If a client device tries to renew the IP address at a later time, the client might obtain a valid IP address. There may be a few reasons for the client device's initial failure to obtain a valid DHCP IP address. First, a temporary glitch may have occurred in the network causing a packet loss. For example, in a classroom when all students come for a class and their client devices associate with the network during the same period of time, a few of the client devices might encounter packet losses due to temporary network congestion. Those few client devices may fall back to use automatic IP addresses. Second, a temporary DHCP server failure may have occurred. Third, the DHCP lease may be temporarily unavailable.
Some client devices have mechanisms to retransmit network requests for DHCP IP address assignment in the event of a failure. For example, a Windows® client device will typically retransmit DHCP requests for three times. Specifically, the client device may send the first retry message after 4 seconds, the next retry message after 8 seconds, and the last retry message after 16 seconds. This mechanism leads to roughly 28 seconds before falling to a self-assigned automatic IP address. This process can be repeated after 30 seconds and/or every 6 minutes or so thereafter. Nevertheless, there is no existing mechanism that allows the client device to re-initiate the DHCP IP address requesting process faster upon an initial failure to obtain a valid DHCP IP address by the client device.
Therefore, client devices may benefit from an intervening mechanism to help them receive valid DHCP IP addresses in cases of an initial failed attempt. This will improve overall network customer experience.